help I’ve lost them

aLL my emerald crabs and peppermint shrimp have vanished. What would cause this? Please help!

Edited by bugzme

uhh...mortality?

Is this upstairs or downstairs?

Assuming your alk and Ca are good, are there any other crabs or grammerus left?

By the way, I'm still not thinking that was the case with your tank.  I think your tank is healthy, so I'm still leaning towards the pH/ALK shift.

Adam

Any major salinity fluxes???

Okay, and what about your Hermit Crabs?

Slightly low Alk is part of the reason coupled with the increase in Bryopsis, low pH and who knows what else. When I was there you told me two things, that you were concerned with the reduced polyp extension and were planning to trade up to a bigger skimmer.

Here are the points that come to my mind:

1. Increase Alk, conversely allowing the Ca to drop. Alk of 9-11 and Ca of 350+ would be the goal at this point, but don't move it that far too fast. Allow a week or two. It may not even reach those numbers but start the process and see where it goes.

2. Work on increasing pH. Do the test that JFinch recommends. Bubble it with an air stone using outside air or if you have no air pump, shake it furiously while outdoors to expose the sample to outside air and see what pH reading it gives.

3. Use some activated carbon and see if there is an increase in polyp extension within 3-4 days.

4. Rip out the bryopsis as much as possible and more frequently. I have a hunch, and it's just a gut feeling at this point, that B contributes to associated reef problems. It may be that it is toxic if it is the sole source of algae. I've seen other tanks that coudn't grow so well with a large growth of B. Have you contacted SSpargur yet about his experience with B?

Edited by Mark Peterson

Well if the hermits are still kicking then the problem is not drastic, but IMO you are right to be giving this some attention for the long-term health of the system.